Single-ply resilient tissue products

ABSTRACT

The present invention provides tissue webs and products having improved z-directional properties. The improved z-directional properties may be achieved by providing the structure with a unique three-dimensional surface topography, which increases the structure&#39;s Exponential Compression Modulus (K) and Caliper Under Load (C0). By improving both K and C0, the present inventors have also been able to provide tissue structures with relatively high Compression Energy (E), which enables the structures to be calendered at high loads without significant loss of sheet bulk or degradation of strength.

RELATED APPLICATIONS

The present application is a divisional application and claims priorityto U.S. patent application Ser. No. 16/467,547, filed on Jun. 7, 2019,which is a national-phase entry, under 35 U.S.C. § 371, of PCT PatentApplication No. PCT/US18/33606, filed on May 21, 2018, which claims thebenefit of U.S. Provisional Application No. 62/509,310, filed May 22,2017, all of which are incorporated herein by reference.

BACKGROUND

Today there is an ever increasing demand for soft, bulky tissueproducts, which also have sufficient tensile strength to withstand use.Traditionally the tissue maker has solved the problem of increasingsheet bulk without compromising strength and softness by adopting tissuemaking processes that only minimally compress the tissue web duringmanufacture, such as through-air drying. Although such techniques haveimproved sheet bulk, they have their limitations. For example, to obtainsatisfactory softness the through-air dried tissue webs often need to becalendered, which may negate much of the bulk obtained by through-airdrying. Calendering may also degrade strength to a point that theproduct fails in use. Thus the tissue maker, and particularly makers ofthrough-air dried tissue products, is often faced with trading offimportant product properties such as strength, softness and bulk.

Complicating matters further is the consumer's desire for tissues thatare aesthetically pleasing with good handfeel. Again, the tissue makeris forced to balance competing properties—provide a smooth sheet withgood handfeel, but poor aesthetics or a visually appealing sheet havinga high degree of topography, but poor handfeel.

Accordingly, there exists a need for tissue structures that are not onlysoft and strong, but also, smooth, bulky and aesthetically pleasing.

SUMMARY

It has now been surprisingly discovered that tissue webs and products,such as rolled bath tissue or towel products, having many of consumerdesired attributes—softness, strength, bulk, smoothness andaesthetics—may be provided by improving the z-directional properties,such as compression modulus and compression energy, of the structure.More particularly, it has been discovered that tissue webs and productshaving improved z-directional properties may be formed bynon-compressively dewatering the nascent tissue web while supporting theweb with a structured papermaking fabric comprising a plurality ofelements having a height less than about 0.7 mm, such as from about 0.4to about 0.7 mm. The elements, which extend in the z-direction above theplane of the papermaking fabric provide the nascent tissue web with athree-dimensional topography and improved z-directional properties.

Accordingly, in one embodiment the present invention provides tissueproducts having aesthetically appealing three-dimensional surfacetopography and improved z-directional properties, such as a CompressionEnergy (E) greater than about 0.0100 J/mm², such as from about 0.0100 toabout 0.0130 J/mm². The improved z-directional properties result in manyconsumer preferred attributes and improve the processing of the tissueproducts. For example, the instant tissue products can withstand highcalender loads, which yields a tissue product that is relatively smoothand soft.

In other embodiments the present disclosure provides a single-plynon-compressively dewatered tissue product having a basis weight fromabout 25 to about 60 grams per square meter (gsm), a sheet bulk greaterthan about 15 cc/g and a Compression Energy (E) greater than about0.0100 J/mm², such as from about 0.0100 to about 0.0130 J/mm².

In another embodiment the invention provides a single-plynon-compressively dewatered tissue product having a basis weight fromabout 25 to about 60 gsm, a geometric mean tensile (GMT) strengthgreater than about 500 g/3″, a Stiffness Index less than about 10, suchas from about 3.0 to about 10, and more preferably from about 4.0 toabout 6.0, and a Compression Energy (E) greater than about 0.0100 J/mm²,such as from about 0.0100 to about 0.0130 J/mm².

In still other embodiments the present invention provides a single-plythrough-air dried tissue product having a first side with atopographical pattern disposed thereon, the pattern comprising aplurality of substantially machine direction oriented line elements, theproduct having a basis weight from about 25 to about 60 gsm, a GMTgreater than about 500 g/3″, a Stiffness Index less than about 10.0,such as from about 3.0 to about 10.0, and more preferably from about 4.0to about 6.0, and a Compression Energy (E) greater than about 0.0100J/mm², such as from about 0.0100 to about 0.0130 J/mm².

In yet other embodiments the present invention provides a single-plythrough-air dried tissue product having a first side with atopographical pattern disposed thereon, the pattern comprising aplurality of substantially machine direction oriented line elements, theproduct having a basis weight from about 25 to about 60 gsm, a GMTgreater than about 500 g/3″, a caliper greater than about 600 μm, suchas from about 600 and to about 700 μm, and a TS7 value less than about10.0.

In still other embodiments the present invention provides a single-plynon-compressively dewatered tissue product having a caliper greater thanabout 600 μm, such as from about 600 and to about 700 μm, a StiffnessIndex less than about 7.5 and more preferably less than about 6.0, and aCompression Energy (E) from about 0.0100 to about 0.0130 J/mm².

In other embodiments the invention provides a rolled tissue productcomprising a single-ply non-compressively dewatered tissue web woundinto a roll, the web having a basis weight from about 25 to about 60gsm, a GMT from about 800 to about 1,500 g/3″, a Stiffness Index lessthan about 10, and a Compression Energy (E) greater than about 0.0100J/mm², such as from about 0.0100 to about 0.0130 J/mm², the wound rollhaving a Firmness less than about 8.0 mm and a Roll Structure greaterthan about 1.25.

In still other embodiments the present invention provides a method ofmanufacturing a soft and resilient tissue product comprising the stepsof forming a fiber slurry, depositing the fiber slurry on a formingfabric, partially dewatering the slurry to form a wet tissue web,transferring the wet tissue web to a through-air drying fabriccomprising a support structure and a plurality of linear elementsextending in the z-direction therefrom, the elements having a heightfrom about 0.4 to about 0.7 mm, through-air drying the wet tissue web toform a dried tissue web, calendering the dried tissue web and windingthe calendered web into a rolled tissue product. In particularlypreferred embodiments the foregoing method results in a rolled tissueproduct having a Firmness less than about 7.5 mm, wherein the tissueproduct has a sheet bulk greater than about 15.0 cc/g and a StiffnessIndex less than about 7.5.

In yet other embodiments the present invention provides a method ofmanufacturing a soft and resilient tissue product comprising the stepsof forming a fiber slurry, depositing the fiber slurry on a formingfabric, partially dewatering the slurry to form a wet tissue web,transferring the wet tissue web to a through-air drying fabriccomprising a support structure and a plurality of linear elementsextending in the z-direction therefrom, the elements having a heightfrom about 0.5 to about 0.7 mm, through-air drying the wet tissue web toform a dried tissue web, calendering the dried tissue web at a calenderload greater than about 40 pli, and more preferably greater than about100 pli, such as from about 100 to about 200 pli and more preferablyfrom about 120 to about 160 pli, and winding the calendered web into arolled tissue product.

Tissue products manufactured according to the foregoing embodimentsgenerally have a high degree of sheet bulk, such as greater than about14.0 cc/g and more preferably greater than about 15.0 cc/g, despitebeing subjected to relatively high levels of calendering, and may havelow TS7 values, such as less than about 10.5 at relatively modest GMT,such as from about 500 to about 1,100 g/3″.

Other features and aspects of the present invention are discussed ingreater detail below.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a fabric useful in the manufacture of tissue websaccording to one embodiment of the present invention;

FIG. 2 is top perspective view of a fabric useful in the manufacture oftissue webs according to one embodiment of the present invention;

FIG. 3 is a cross section view of a fabric useful in the manufacture oftissue webs according to one embodiment of the present invention takenthrough line 3-3 of FIG. 2;

FIG. 4 is a perspective view of a tissue web according to one embodimentof the present invention;

FIG. 5 is a cross section view of the tissue web of FIG. 4 through line5-5;

FIG. 6 is a graph plotting the effect of bead height (x-axis) on thecaliper (y-axis) of base sheet (-♦-) and tissue products calendered attwo different loads (150 PLI -▴- and 40 PLI -▪-);

FIG. 7 is a graph plotting the effect of bead height (x-axis) on TS750(y-axis) of tissue products calendered at two different loads (150 PLI-▴- and 40 PLI -▪-); and

FIG. 8 is a graph plotting the effect of bead height (mm, x-axis) onCompression Energy (J/mm², y-axis) of tissue products calendered at twodifferent loads (150 PLI -▴- and 40 PLI -▪-).

DEFINITIONS

As used herein the term “tissue web” refers to a structure comprising aplurality of elongated particulates having a length to diameter ratiogreater than about 10 such as, for example, papermaking fibers and moreparticularly pulp fibers, including both wood and non-wood pulp fibers,and synthetic staple fibers. A non-limiting example of a tissue web is awet-laid sheet material comprising pulp fibers.

As used herein the term “tissue product” refers to products made fromtissue webs and includes, bath tissues, facial tissues, paper towels,industrial wipers, foodservice wipers, napkins, medical pads, and othersimilar products. Tissue products may comprise one, two, three or moreplies.

As used herein the term “ply” refers to a discrete tissue web used toform a tissue product.

Individual plies may be arranged in juxtaposition to each other.

As used herein the term “layer” refers to a plurality of strata offibers, chemical treatments, or the like within a ply.

As used herein the “topographical pattern” generally refers to a patterndisposed on at least one surface of the tissue web in accordance withthe present invention. The topographical pattern generally texturizesthe surface of the tissue web providing the surface with a first and asecond elevation. The topographical pattern may comprise a plurality ofline elements, such as a plurality of line elements that aresubstantially oriented in the machine direction of the tissue web.

As used herein the term “line element” refers to a topographical patternin the shape of a line, which may be a continuous, discrete,interrupted, and/or partial line with respect to a tissue web on whichit is present. The line element may be of any suitable shape such asstraight, bent, kinked, curled, curvilinear, serpentine, sinusoidal, andmixtures thereof that may form regular or irregular periodic ornon-periodic lattice work of structures wherein the line elementexhibits a length along its path of at least 10 mm. In one example, theline element may comprise a plurality of discrete elements, such as dotsand/or dashes for example, that are oriented together to form a lineelement.

As used herein the term “continuous element” refers to an elementdisposed on a carrier structure useful in forming a tissue web or atopographical pattern that extends without interruption throughout onedimension of the carrier structure or the tissue web.

As used herein the term “discrete element” refers to separate,unconnected elements disposed on a carrier structure useful in forming atissue web or on the surface of a tissue web that do not extendcontinuously in any dimension of the support structure or the tissue webas the case may be.

As used herein the term “curvilinear decorative element” refers to anyline or visible pattern that contains either straight sections, curvedsections, or both that are substantially connected visually. Curvilineardecorative elements may appear as undulating lines, substantiallyconnected visually, forming signatures or patterns.

As used herein “decorative pattern” refers to any non-random repeatingdesign, figure, or motif. It is not necessary that the curvilineardecorative elements form recognizable shapes, and a repeating design ofthe curvilinear decorative elements is considered to constitute adecorative pattern.

As used herein the term “basis weight” generally refers to the bone dryweight per unit area of a tissue and is generally expressed as grams persquare meter (gsm). Basis weight is measured using TAPPI test methodT-220. While basis weight may be varied, tissue products preparedaccording to the present invention generally have a basis weight greaterthan about 10 gsm, such as from about 10 to about 60 gsm, morepreferably from about 25 to about 55 gsm and still more preferably fromabout 30 to about 50 gsm.

As used herein the term “caliper” is the representative thickness of asingle sheet (caliper of tissue products comprising two or more plies isthe thickness of a single sheet of tissue product comprising all plies)measured in accordance with TAPPI test method T402 using an EMVECO 200-AMicrogage automated micrometer (EMVECO, Inc., Newberg, Oreg.). Themicrometer has an anvil diameter of 2.22 inches (56.4 mm) and an anvilpressure of 132 grams per square inch (per 6.45 square centimeters) (2.0kPa). The caliper of a tissue product may vary depending on a variety ofmanufacturing processes and the number of plies in the product, however,tissue products prepared according to the present invention generallyhave a caliper greater than about 500 μm, more preferably greater thanabout 575 μm and still more preferably greater than about 600 μm, suchas from about 500 to about 1,000 μm and more preferably from about 600to about 750 μm.

As used herein the term “sheet bulk” refers to the quotient of thecaliper (generally having units of μm) divided by the bone dry basisweight (generally having units of gsm). The resulting sheet bulk isexpressed in cubic centimeters per gram (cc/g). Tissue products preparedaccording to the present invention generally have a sheet bulk greaterthan about 10.0 cc/g, more preferably greater than about 12.0 cc/g andstill more preferably greater than about 14.0 cc/g, such as from about10.0 to about 20.0 cc/g and more preferably from about 12.0 to about16.0 cc/g.

As used herein, the terms “geometric mean tensile” and “GMT” refer tothe square root of the product of the machine direction tensile strengthand the cross-machine direction tensile strength of the tissue product.While the GMT may vary, tissue products prepared according to thepresent invention generally have a GMT greater than about 700 g/3″, morepreferably greater than about 750 g/3″ and still more preferably greaterthan about 800 g/3″, such as from about 700 to about 1,500 g/3″.

As used herein, the term “slope” refers to slope of the line resultingfrom plotting tensile versus stretch and is an output of the MTSTestWorks™ in the course of determining the tensile strength asdescribed in the Test Methods section herein. Slope is reported in theunits of grams (g) per unit of sample width (inches) and is measured asthe gradient of the least-squares line fitted to the load-correctedstrain points falling between a specimen-generated force of 70 to 157grams (0.687 to 1.540 N) divided by the specimen width. Slopes aregenerally reported herein as having units of grams (g) or kilograms(kg).

As used herein, the term “geometric mean slope” (GM Slope) generallyrefers to the square root of the product of machine direction slope andcross-machine direction slope. GM Slope generally is expressed in unitsof kilograms (kg). While the GM Slope may vary, tissue products preparedaccording to the present invention generally have a GM Slope less thanabout 6.5 kg, more preferably less than about 6.0 kg and still morepreferably less than about 5.5 kg, such as from about 4.5 to about 6.5kg.

As used herein, the term “Stiffness Index” refers to GM Slope (havingunits of kg), divided by GMT (having units of g/3″) multiplied by 1,000.While the Stiffness Index may vary, tissue products prepared accordingto the present invention generally have a Stiffness Index less thanabout 7.5, more preferably less than about 7.0 and still more preferablyless than about 6.0 such as from about 4.5 to about 7.5.

As used herein, the term “Roll Firmness” generally refers to the abilityof a rolled tissue product to withstand deflection when impacted, whichis determined as described in the Test Methods section.

As used herein, the term “Roll Structure” generally refers to theoverall appearance and quality of a rolled tissue product and is theproduct of Roll Bulk (expressed in cc/g) and caliper (expressed in cm)divided by Firmness (expressed in cm). Roll Structure is generallyreferred to herein without reference to units.

As used herein, the terms “T57” and “TS7 value” refer to the output ofthe EMTEC Tissue Softness Analyzer (commercially available from EmtecElectronic GmbH, Leipzig, Germany) as described in the Test Methodssection. TS7 has units of dB V2 rms, however, TS7 may be referred toherein without reference to units. The TS7 value is the frequency peakthat occurs around 6.5 kHz on the noise spectrum graph output from theEMTEC Tissue Softness Analyzer. This peak represents the softness of thesample. Generally, softer samples produce a lower TS7 peak. In certainembodiments the invention provides through-air dried tissue productshaving a TS7 less than about 11.0 and more preferably less than about10.5, such as from about 8.0 to about 11.0. The foregoing TS7 values aregenerally achieved at geometric mean tensile strengths from about 500 toabout 1,500 g/3″.

As used herein, terms “TS750” and “TS750 value” refer to the output ofthe EMTEC Tissue Softness Analyzer (commercially available from EmtecElectronic GmbH, Leipzig, Germany) as described in the Test Methodssection. TS750 has units of dB V2 rms, however, TS750 may be referred toherein without reference to units. The TS750 value is the frequency peakthat occurs in the range of 200 to 1,000 Hz. This peak represents thesmoothness of the sample. Generally, smoother samples will produce alower TS750 peak. In certain embodiments the invention providesthrough-air dried tissue products having a TS750 less than about 85.0and more preferably less than about 80.0, such as from about 70.0 toabout 85.0. The foregoing TS750 values are generally achieved atgeometric mean tensile strengths from about 500 to about 1,500 g/3″.

As used herein, the term “Stiffness Parameter” (D) refers to the outputof the EMTEC Tissue Softness Analyzer (commercially available from EmtecElectronic GmbH, Leipzig, Germany) as described in the Test Methodssection. Stiffness Parameter typically has units of mm/N and is ameasure of the deformation of a sample under a defined load. While theStiffness Parameter of tissue webs and products prepared according tothe present invention may vary, in certain embodiments, products have aStiffness Parameter less than about 3.5 mm/N and more preferably lessthan about 3.0 mm/N, such as from about 2.5 to about 3.5 mm/N and morepreferably from about 2.75 to about 3.25 mm/N.

As used herein, the term “through-air dried” generally refers to amethod of manufacturing a tissue web where a drying medium, such asheated air, is blown through a perforated cylinder, the embryonic tissueweb and the fabric supporting the web. Generally the embryonic tissueweb is supported by the fabric and is not brought into contact with theperforated cylinder.

As used herein, the term “S90” generally refers to the smoothness of atissue web or product and is an output of the FRT MicroSpy® Profileprofilometer analysis described in the Test Methods section below. S90generally has units of millimeters (mm).

As used herein, “noncompressive dewatering” and “noncompressive drying”refer to dewatering or drying methods, respectively, for removing waterfrom tissue webs that do not involve compressive nips or other stepscausing significant densification or compression of a portion of the webduring the drying or dewatering process. In particularly preferredembodiments the wet web is wet-molded in the process of noncompressivedewatering to improve the three-dimensionality and absorbent propertiesof the web.

As used herein, the term “Compression Energy” generally refers to theenergy required to compress a tissue web or product from an initialcaliper under little or no load to a lower caliper under a greater load.Compression Energy (E) is calculated by integrating the compressioncurve from the initial height down to the compressed caliper asdescribed in the Test Methods section below. Here, “Compression Energy”is calculated from the second compressive cycle. Compression Energy mayhave units of Joules per square millimeter (J/mm²).

As used herein, the term “Exponential Compression Modulus” (K) generallyrefers to the dry compression resiliency of a tissue web or product.Exponential Compression Modulus (K) is found by least squares fitting ofthe caliper (C) and pressure data from a compression curve for a sampleas described in the Test Methods section below. Exponential CompressionModulus (K) is dimensionless.

As used herein, the term “Caliper Under Load” (C₀) generally refers tothe caliper of a stack of ten tissue products under the 0.002 MPareference pressure and has units of millimeters or microns. Themeasurement is taken when measuring compression energy described belowin the Test Methods section.

DETAILED DESCRIPTION

The present invention provides a variety of novel non-compressivelydewatered tissue webs and products having a topographical patterndisposed on at least one surface. The present non-compressivelydewatered tissue webs and products have improved z-directionalproperties, such as relatively high compression energy, which make themmore easily processed and convertible to rolled tissue products havinggood roll structure and firmness. At the same time, the structures andresulting tissue products retain many of desirable attributes, such ashigh bulk, sufficient strength to withstand use, smoothness andsoftness.

The improved z-directional properties have been achieved by providingthe structure with a unique three-dimensional surface topography. Theunique topography increases both the Exponential Compression Modulus (K)and the Caliper Under Load (C₀). By improving both K and C₀, the presentinventors have also been able to provide tissue structures withrelatively high compression Energy, which enables the structures to becalendered at high loads without significant loss of sheet bulk ordegradation of strength. For example, the inventive structures may becalendered at loads in excess of 100 pli yet retain more than about 65percent of their initial sheet bulk. When prior art structures aresubjected to similar loads they retain less than about 50 percent oftheir initial sheet bulk.

Further, the ability to calender at high loads without significant lossof sheet bulk or degradation of strength results in tissue productshaving excellent surface properties, such as improved smoothness(measured as TS750) and softness (measured as TS7). For example, thepresent invention provides tissue products having a TS7 less than about10.5 and a TS750 less than about 85.0.

Thus, in certain embodiments, tissue webs and products preparedaccording to the present invention may have improved Compression Energy(E), such as E greater than about 0.01000 J/mm², such as from about0.0100 to about 0.0130 J/mm² and more preferably from about 0.01100 toabout 0.0130 J/mm². Tissue products having the foregoing CompressionEnergy generally have an Exponential Compression Modulus (K) greaterthan about 5.0 and more preferably greater than about 5.2 and still morepreferably greater than about 5.3, such as from about 5.0 to about 5.5.In other embodiments the inventive tissue products have a Co greaterthan about 9.0 mm and more preferably greater than about 9.4 mm andstill more preferably greater than about 9.8 mm, such as from about 9.0to about 10.2 mm.

Tissue products having improved z-directional properties also have goodinter-fiber bonding and bulk. As such inventive tissue productsgenerally have geometric mean tensile strengths greater than about 700g/3″, such as from about 700 to about 1,500 g/3″ and more preferablyfrom about 800 to about 1,250 g/3″ while having good sheet bulk, such asgreater than about 10 cc/g and more preferably greater than about 12cc/g and still more preferably greater than about 14 cc/g, such as fromabout 10 to about 18 cc/g and more preferably from about 14 to about 18cc/g.

In other embodiments, in addition to having good z-directionalproperties, such as improved E, K and C₀, the instant tissue webs andproducts have relatively low stiffness. For example, in certainembodiments tissue webs and products prepared according to the presentinvention generally have a Stiffness Index less than about 7.5, morepreferably less than about 6.0 and still more preferably less than about5.0 such as from about 4.5 to about 7.5. These improvements deliver uponconsumer's desire for a more cushiony tissue product, with low stiffnessand good handfeel.

Generally the tissue webs of the present invention comprise a threedimension topographical pattern, often referred to herein simply as atopographical pattern, on at least one of its surfaces. Preferably thepattern is imparted during the manufacturing process such as by wettexturing during formation of the web, molding the pattern into the webusing a drying fabric or by embossing. The pattern is not the result ofprinting, which generally would not result in a three dimensionaltopographical pattern. As such the tissue webs of the present inventionare generally free from bonding materials applied to the surface byprinting, or the like. Further, tissue webs of the present invention aregenerally produced without the use of latex bonding materials such asacrylates, vinyl acetates, vinyl chlorides and methacrylates. Ratherthan having printed patterns the instant tissue webs have patterns thatare formed by wet molding and/or through-air drying via a fabric and/oran imprinted through-air drying fabric.

Accordingly, in one embodiment, the topographical pattern is formedduring the manufacturing process by molding the tissue web using anendless belt having a corresponding topographical pattern. For example,as illustrated in FIG. 1, the tissue web may be manufactured using anendless belt 10 comprising a continuous three dimensional element 40,also referred to simply as a continuous line element, and a reinforcingstructure 30 (also referred to herein as a carrier structure or fabric).The reinforcing structure 30 comprises a pair of opposed majorsurfaces—a web contacting surface 64 from which the continuous lineelements 40 extend and a machine contacting surface 62. Machineryemployed in a typical papermaking operation is well known in the art andmay include, for example, vacuum pickup shoes, rollers, and dryingcylinders. In one embodiment the belt comprises a through-air dryingfabric useful for transporting an embryonic tissue web across dryingcylinders during the tissue manufacturing process. In such embodimentsthe web contacting surface 64 supports the embryonic tissue web, whilethe opposite surface, the machine contacting surface 62, contacts thethrough-air dryer.

Generally the continuous line element 40 is disposed on theweb-contacting surface 64 for cooperating with, and structuring of, thewet fibrous web during manufacturing. In a particularly preferredembodiment the web contacting surface 64 comprises a plurality of spacedapart three dimensional elements distributed across the web-contactingsurface 64 of the carrier structure 50 and together constituting from atleast about 15 percent of the web-contacting surface, such as from about15 to about 35 percent, more preferably from about 18 to about 30percent, and still more preferably from about 20 to about 25 percent ofthe web-contacting surface.

In addition to continuous line elements 40 the web-contacting surface 64preferably comprises a plurality of continuous landing areas 60. Thelanding areas 60 are generally bounded by the elements 40 andcoextensive with the top surface plane 50 of the belt 10. Landing areas60 are generally permeable to liquids and allow water to be removed fromthe cellulosic tissue web by the application of differential fluidpressure, by evaporative mechanisms, or both when drying air passesthrough the embryonic tissue web while on the papermaking belt 10 or avacuum is applied through the belt 10. Without being bound by anyparticularly theory, it is believed that the arrangement of elements andlanding areas allow the molding of the embryonic web causing fibers todeflect in the z-direction and generate the caliper of, and patterns onthe resulting tissue web.

The carrier structure 30 has two principle dimensions—a machinedirection (“MD”), which is the direction within the plane of the belt 10parallel to the principal direction of travel of the tissue web duringmanufacture and a cross-machine direction (“CD”), which is generallyorthogonal to the machine direction. The carrier structure 30 isgenerally permeable to liquids and air. In one particularly preferredembodiment the carrier structure is a woven fabric. The carrierstructure may be substantially planar or may have a three dimensionalsurface defined by ridges. In one embodiment the carrier structure is asubstantially planar woven fabric such as a multi-layered plain-wovenfabric 30 having base warp yarns 32 interwoven with shute yarns 34 in a1×1 plain weave pattern. One example of a suitable substantially planarwoven fabric is disclosed in U.S. Pat. No. 8,141,595, the contents ofwhich are incorporated herein in a manner consistent with the presentinvention. In a particularly preferred embodiment, the carrier structurecomprises a substantially planar woven fabric wherein the plain-weaveload-bearing layer is constructed so that the highest points of both theload-bearing shutes 34 and the load-bearing warps 32 are coplanar andcoincident with the plane 70.

With further reference to FIGS. 1 and 2 a plurality of continuouselements 40 are disposed on the web-contacting surface 64 of the carrierstructure 30. Each element 40 has a first dimension in a first directionin the plane of the top surface area, a second dimension in a seconddirection in the plane of the top surface area, the first and seconddirections being at right angles to each other. The extent of theelement 40 in the first direction generally defines the element width(w). The continuous element 40 further comprises a top surface area 48extending substantially along the second direction and a pair of opposedsidewalls 45, 47 extending in the z-direction and having a mean height(h). These dimensions being defined when the belt is in an uncompressedstate.

The continuous elements 40 generally extend in the z-direction(generally orthogonal to both the machine direction and cross-machinedirection) above the plane 70 of the carrier structure 30. The elementsmay have straight sidewalls or tapered sidewalls and be made of anymaterial suitable to withstand the temperatures, pressures, anddeformations which occur during the papermaking process. In theembodiment illustrated in FIG. 3 the continuous elements 40 aresimilarly sized and have generally straight, parallel sidewalls 45, 47providing the continuous elements 40 with a width (w), and a height (h).The width (w) and the height (h) may be varied depending on the desireddegree of molding and the resulting tissue product properties. Incertain embodiments the height (h) is less than about 0.7 mm, such asfrom about 0.5 and 0.7 mm. The height (h) is generally measured as thedistance between the plane of the carrier structure and the top plane ofthe elevations.

Further, the continuous elements 40 may have a width (w) from about 0.5to about 0.8 mm, and more preferably from about 0.6 to about 0.7 mm. Thewidth is generally measured normal to the principal dimension of theelevation within the plane of the belt at a given location. Where theelement 40 has a generally square or rectangular cross-section, thewidth (w) is generally measured as the distance between the two planarsidewalls 45, 47 that form the element 40. In those cases where theelement does not have planar sidewalls, the width is measured along thebase of the element at the point where the element contacts the carrier.

In a particularly preferred embodiment the continuous elements 40 haveplanar sidewalls 45, 47 such that the cross-section of the element hasan overall square or rectangular shape. However, it is to be understoodthat the design element may have other cross-sectional shapes, such astriangular, convex or concave, which may also be useful in producinghigh bulk tissue products according to the present invention.Accordingly, in a particularly preferred embodiment the continuouselements 40 preferably have planar sidewalls 45, 47 and a squarecross-section where the width (w) and height (h) are equal and vary fromabout 0.5 and 0.7 mm.

The spacing and arrangement of continuous elements may vary depending onthe desired tissue product properties and appearance. In one embodimenta plurality of elements extend continuously throughout one dimension ofthe belt and each element in the plurality is spaced apart from theadjacent element. Thus, the elements may be spaced apart across theentire cross-machine direction of the belt, may endlessly encircle thebelt in the machine direction, or may run diagonally relative to themachine and cross-machine directions. Of course, the directions of theelements alignments (machine direction, cross-machine direction, ordiagonal) discussed above refer to the principal alignment of theelements. Within each alignment, the elements may have segments alignedat other directions, but aggregate to yield the particular alignment ofthe entire elements.

Generally the elements are spaced apart from one another so as to definea landing area there-between. In use, as the embryonic tissue web isformed fibers are deflected in the z-direction by the continuouselements, however, the spacing of elements is such that the webmaintains a relatively uniform density. This arrangement provides thebenefits of improved web extensibility, increased sheet bulk, bettersoftness, and a more pleasing texture.

If the individual elements are too high, or the landing area is toosmall, the resulting sheet may have excessive pinholes and insufficientcompression resistance, CD stretch, and CD TEA, and be of poor quality.Further, tensile strength may be degraded if the span between elementsgreatly exceeds the fiber length. Conversely, if the spacing betweenadjacent elements is too small the tissue will not mold into the landingareas without rupturing the sheet, causing excessive sheet holes, poorstrength, and poor paper quality.

In addition to varying the spacing and arrangement of the elements alongthe carrier structure, the shape of the element may also be varied. Forexample, in one embodiment, the elements are substantially sinusoidaland are arranged substantially parallel to one another such that none ofthe elements intersect one another. As such, in the illustratedembodiment, the adjacent sidewalls of individual elements are equallyspaced apart from one another. In such embodiments, the center-to-centerspacing of design elements (also referred to herein as pitch or simplyas p) may be greater than about 1.0 mm, such as from about 1.0 to about20 mm apart and more preferably from about 2.0 to about 10 mm apart. Inone particularly preferred embodiment the continuous elements are spacedapart from one-another from about 2.5 to about 4.0 mm. This spacing willresult in a tissue web which generates maximum caliper when made ofconventional cellulosic fibers. Further, this arrangement provides atissue web having three dimensional surface topography, yet relativelyuniform density.

In other embodiments the continuous elements may occur as wave-likepatterns that are arranged in-phase with one another such that the pitch(p) is approximately constant. In other embodiments elements may form awave pattern where adjacent elements are offset from one another.Regardless of the particular element pattern, or whether adjacentpatterns are in or out of phase with one another, the elements areseparated from one another by some minimal distance. Preferably thedistance between continuous elements is greater than 0.5 mm and in aparticularly preferred embodiment greater than about 1.0 mm and stillmore preferably greater than about 2.0 mm such as from about 2.0 toabout 6.0 mm and still more preferably from about 2.5 to about 4.0 mm.

Where the continuous elements are wave-like, the elements have anamplitude (A) and a wavelength (L). The amplitude may range from about2.0 to about 200 mm, in a particularly preferred embodiment from about10 to about 40 mm and still more preferably from about 18 to about 22mm. Similarly, the wavelength may range from about 20 to about 500 mm,in a particularly preferred embodiment from about 50 to about 200 mm andstill more preferably from about 80 to about 120 mm.

While in certain embodiments the elements are continuous the inventionis not so limited. In other embodiments the elements may be discrete.For clarity, the discrete elements will be referred to herein asprotuberances. Generally the protuberances are discrete and spaced apartfrom one another. Each protuberance is joined to a reinforcing structureand extends outwardly from the web contracting plane of the reinforcingstructure. In this manner the protuberances contact the tissue webduring manufacture.

The protuberances may have a square horizontal and lateral (relative tothe plane of the carrier structure) cross-sectional shape, however, theshape is not so limited. The protuberance may have any number ofdifferent horizontal and lateral cross-sectional shapes. For example,the horizontal cross-section may have a rectangular, circular, oval,polygonal or hexagonal shape. A particularly preferred protuberance hasplanar sidewalls which are generally perpendicular to the plane of thecarrier structure. Alternatively, the protuberances may have a taperedlateral cross-section formed by sides that converge to yield aprotuberance having a base that is wider than the distal end.

The individual protuberances may be arranged in any number of differentmanners to create a decorative pattern. In one particular embodimentprotuberances are spaced and arranged in a non-random pattern so as tocreate a wave-like design. In the illustrated embodiment spaced betweenthe decorative patterns are landing areas that provide a visuallydistinctive interruption to the decorative pattern formed by theindividual spaced apart protuberances. In this manner, despite beingdiscrete elements, the protuberances are spaced apart so as to form avisually distinctive curvilinear decorative element that extendssubstantially in the machine direction. Taken as a whole the discreteelements forms a wave-like pattern.

In other embodiments the protuberances may be spaced and arranged so asto form a decorative figure, icon or shape such as a flower, heart,puppy, logo, trademark, word(s), and the like. Generally the designelements are spaced about the support structure and can be equallyspaced or may be varied such that the density and the spacing distancemay be varied amongst the design elements. For example, the density ofthe design elements can be varied to provide a relatively large orrelatively small number of design elements on the web. In a particularlypreferred embodiment the design element density, measured as thepercentage of background surface covered by a design element, is fromabout 10 to about 35 percent and more preferably from about 20 to about30 percent. Similarly the spacing of the design elements can also bevaried, for example, the design elements can be arranged in spaced apartrows. In addition, the distance between spaced apart rows and/or betweenthe design elements within a single row can also be varied.

In certain embodiments the plurality of protuberances defining a givendesign element may be spaced apart from one another so as to definelanding areas there between. The landing areas are generally bounded bythe designs and coextensive with the top surface plane of the carrierstructure. Landing areas are generally permeable to liquids and allowwater to be removed from the cellulosic tissue web by the application ofdifferential fluid pressure, by evaporative mechanisms, or both whendrying air passes through the embryonic tissue web while on thepapermaking belt or a vacuum is applied through the belt.

The elements may be formed from a polymeric material, or other material,applied and joined to the carrier structure in any suitable manner. Thusin certain embodiments elements are formed by extruding, such as thatdisclosed in U.S. Pat. No. 5,939,008, the contents of which areincorporated herein by reference in a manner consistent with the presentinvention, or printing, such as that disclosed in U.S. Pat. No.5,204,055, the contents of which are incorporated herein by reference ina manner consistent with the present invention, a polymeric materialonto the carrier structure. In other embodiments the design element maybe produced, at least in some regions, by extruding or printing two ormore polymeric materials.

The above mentioned belts may be used in a variety of processes for themanufacture of tissue webs and products according to the presentinvention. For example, the tissue web can be a wet-creped web, acalendered web, an embossed web, a through-air dried web, a crepedthrough-air dried web, an uncreped through-air dried web, as well asvarious combinations of the above. In one particular embodiment of thepresent invention, however, the tissue web is made in an uncrepedthrough-air dried process. Uncreped through-air dried tissue webs mayprovide various advantages in the process of the present invention. Itshould be understood, however, that other types of tissue webs can beused in the present invention. For example, in an alternativeembodiment, a wet creped tissue web can be utilized.

Tissue webs manufactured by one of the foregoing processes generallyhave a topographical pattern such as discrete line elements, continuousline elements that impart the tissue product with a negative Poisson'sratio and other improved physical properties. An exemplary tissueproduct is illustrated in FIG. 4, which shows a planar tissue product100 having a machine (MD) and a cross-machine (CD) direction. The tissueproduct 100 has a first upper surface 102 and an opposed second lowersurface 104. A wave-like topographical pattern 106 is disposed on thefirst upper surface 102. The wave-like topographical pattern 106comprises a continuous line element substantially oriented in themachine direction (MD). The pattern generally consists of severalwave-like elements 106 separated from one another by the planar surface120 of the tissue web. While the illustrated wave-like topographicalpattern 106 is continuous, in other embodiments the pattern may besemi-continuous or discontinuous.

With reference to FIGS. 4 and 5, the wave-like topographical pattern 106comprises a plurality of spaced apart continuous line elements 118. Eachline element 118 forms an oscillating pattern or wave with alternatingpeaks 110 and valleys 108. The line elements 118 are arranged generallyparallel to one another such that no two line elements intersect oneanother. Further, in a preferred embodiment, the peaks 110 and valleys108 of each element 118 and the valleys and peaks of each adjacentelement are substantially in-phase with one another such that thespacing (P) between adjacent elements is substantially constantthroughout the pattern 106. Generally, the spacing (P) between adjacentelements is measured from the centers of adjacent peaks.

Accordingly, in certain embodiments, the spacing (P) may range fromabout 1.0 to about 10 mm, such as from about 2.0 to about 5.0 mm andmore preferably from about 3.0 to about 4.5 mm. Further, the width (W)of the line elements 118 themselves may range from about 0.5 to about5.0 mm, such as from about 0.75 to about 3.0 mm and more preferably fromabout 0.9 to about 1.5 mm. At the foregoing spacing and widths thetissue webs of the present invention generally comprise from about 2.0to about 4.0 elements per centimeter in the cross-machine direction,more preferably from about 2.2 to about 3.8 line elements percentimeter.

Tissue webs prepared according to the present invention may be convertedinto tissue products using any one of a number of well-known convertingprocesses such as calendering, embossing and winding into rolledproducts. Generally the webs are converted into rolled bath tissue andtowel products, which may comprise one, two or three plies where theplies may be prepared by the same process and be substantially similaror where they are prepared by different processes and have differentproperties.

Compared to tissue products prepared using through-air drying fabricshaving element heights greater than about 0.7 mm, tissue productsprepared according to the present invention generally have improvedz-directional properties, such as improved K, C₀, and Compression Energy(E) and improved softness (measured as TS7). This effect is illustratedin the table below, which compares the physical properties of similarlymanufactured and converted single-ply tissue products. Each of theproducts were manufactured in a substantially identical fashion with theexception of the through-air drying fabric element height.

TABLE 1 Element Height Sheet Bulk GMT Stiffness C₀ E (mm) (cc/g) (g/3″)Index K (mm) (J/mm²) TS7 0.9 14.0 1265 4.80 4.99 8.92 0.00960 11.34 0.814.5 1235 5.22 4.83 9.19 0.00967 10.37 0.6 15.0 1269 4.78 5.23 9.280.01073 9.72

Thus, in certain embodiments the present invention provides anon-compressively dewatered tissue product manufactured using athrough-air drying fabric comprising a plurality of substantiallymachine direction oriented line elements having a height less than about0.7 mm, such as from about 0.5 to about 0.7 mm. The resulting tissueproduct preferably has improved z-directional physical properties, suchas improved K, C₀ and E. For example, in certain embodiments, theinvention provides non-compressively dewatered tissue products having aK greater than about 5.0 and more preferably greater than about 5.2 andstill more preferably greater than about 5.3, such as from about 5.0 toabout 5.5 and a C₀ greater than about 9.0 mm and more preferably greaterthan about 9.4 mm and still more preferably greater than about 9.8 mm,such as from about 9.0 to about 10.2 mm. In other embodiments theinvention provides tissue products having a GMT from about 800 to about1,400 g/3″, a sheet bulk greater than about 15.0, such as from about15.0 to about 16.0 cc/g and a Compression Energy (E) greater than about0.0100 to about 0.00130 J/mm².

In certain embodiments tissue webs produced according to the presentinvention may be subjected to additional processing after formation suchas calendering in order to convert them into tissue products. The tissuewebs of the present invention are surprisingly resilient and retain ahigh degree of bulk compared to similar webs prepared using through-airdrying fabrics having continuous line elements with a height greaterthan about 0.7 mm. A comparison of various tissue webs illustrating thiseffect are shown in the table below.

TABLE 2 Calender Initial Finished Delta Bead Height Load Sheet BulkSheet Bulk Sheet Bulk (mm) (pli) (cc/g) (cc/g) (%) TS7 TS750 0.9 15034.6 14.0 −59% 11.34 99.45 0.8 150 26.6 14.5 −46% 10.37 88.49 0.6 15022.9 15.0 −34% 9.72 75.26

In other embodiments, the increased resiliency allows the webs to becalendered to produce a soft tissue product without a significantdecrease in bulk. Thus, the present invention provides bulky single-plythrough-air dried tissue products, such as products having a sheet bulkgreater than about 15.0 cc/g, that are also soft, such as having a TS7less than about 10.5 and more preferably less than about 10.0, such asfrom about 9.0 to about 10.5. In other embodiments, the foregoing tissueproducts may also have improved smoothness, such as a TS750 less thanabout 85.0 and more preferably less than about 80.0, such as from about70.0 to about 85.0.

While the present tissue webs and products have improved softness andsmoothness, in preferred embodiments they comprise a three dimensionalpattern disposed on at least one of their surfaces, which provides thesheet with surface topography. Preferably however, the topography issuch that it is perceived by a consumer as being smooth. Accordingly, incertain embodiments, the surface of the sheet is textured but isrelatively smooth to the touch such that S90 (an output of the FRTMicroSpy® Profile profilometer analysis described in the Test Methodssection below) is less than about 0.60 mm, more preferably less thanabout 0.55 mm and still more preferably less than about 0.50 mm, such asfrom about 0.45 to about 0.60 mm, such as from about 0.45 to about 0.55mm. In a particularly preferred embodiment the invention provides atissue product having a relatively high caliper, such as greater thanabout 500 μm and more preferably greater than about 600 μm and a S90less than about 0.60 mm, such as from about 0.45 to about 0.60 mm, suchas from about 0.55 mm.

In addition to improving resiliency of the structure and enabling highercalendering loads, improvement of z-direction properties facilitatesimproved winding of rolled tissue products. Rolled tissue productsformed according to the present disclosure generally have higher rollbulk at a given roll firmness. Further, the rolls generally have asurprising degree of interlocking between successive wraps of thespirally wound web, improving roll structure at a given roll firmness,more specifically allowing less firm rolls to be made without slippagebetween wraps. One measurement reduced nesting and improved rollstructure, referred to herein as Roll Structure, is the product of RollBulk (expressed in cc/g) and caliper (express in cm) divided by Firmness(expressed in cm). Generally rolled tissue products of the presentinvention have a Roll Structure greater than about 1.0 and morepreferably greater than about 1.25 and still more preferably greaterthan about 1.5, such as from about 1.0 to about 1.75. The foregoing RollStructures are achieved at relatively high roll bulks, such as greaterthan about 10 cc/g and more preferably greater than about 12 cc/g, suchas from about 10 to about cc/g.

TEST METHODS Tissue Softness

Tissue softness was measured using an EMTEC Tissue Softness Analyzer(“TSA”) (Emtec Electronic GmbH, Leipzig, Germany). The TSA comprises arotor with vertical blades which rotate on the test piece applying adefined contact pressure. Contact between the vertical blades and thetest piece creates vibrations, which are sensed by a vibration sensor.The sensor then transmits a signal to a PC for processing and display.The signal is displayed as a frequency spectrum. For measurement of TS7values the blades are pressed against the sample with a load of 100 mNand the rotational speed of the blades is two revolutions per second.

The frequency analysis in the range of approximately 200 to 1000 Hzrepresents the surface smoothness or texture of the test piece. The peakin the frequency range between 200 to 1000 Hz is herein referred to asthe TS750 value and is expressed as dB V2 rms. A high amplitude peakcorrelates to a rougher surface.

A further peak in the frequency range between 6 and 7 kHz represents thesoftness of the test piece. The peak in the frequency range between 6and 7 kHz is herein referred to as the TS7 value and is expressed as dBV2 rms. The lower the amplitude of the peak occurring between 6 and 7kHz, the softer the test piece.

In addition to TS750 and TS7, the analyzer reports a stiffness parameter(D) having units of mm/N. The stiffness parameter (D) is the deformationof the sample under a defined load.

Test samples were prepared by cutting a circular sample having adiameter of 112.8 mm. All samples were allowed to equilibrate at TAPPIstandard temperature and humidity conditions for at least 24 hours priorto completing the TSA testing. Only one ply of tissue is tested.Multi-ply samples are separated into individual plies for testing. Thesample is placed in the TSA with the softer (air contacting side in thecase of uncreped samples or the dryer or Yankee contacting side in thecase of creped samples) side of the sample facing upward. The sample issecured and the measurements are started via the PC. The PC records,processes and stores all of the data according to standard TSA protocol.The reported values are the average of five replicates, each one with anew sample.

Profilometry

The surface properties of tissue webs and products prepared as describedherein were measured by first generating a digital image of the fabriccontacting surface of a sample using an FRT MicroSpy® Profileprofilometer (FRT of America, LLC, San Jose, Calif.) and then analyzingthe image using Nanovea® Ultra software version 6.2 (Nanovea Inc.,Irvine, Calif.). Samples (either base sheet or finished product) werecut into squares measuring 145×145 mm. The samples were then secured tothe x-y stage of the profilometer using tape, with the fabric contactingsurface of the sample facing upwards, being sure that the samples werelaid flat on the stage and not distorted within the profilometer fieldof view.

Once the sample was secured to the stage, the profilometer was used togenerate a three dimension height map of the sample surface. A 1602×1602array of height values were obtained with a 30 μm spacing resulting in a48 mm MD×48 mm CD field of view having a vertical resolution of 100 μmand a lateral resolution of 6 μm. The resulting height map was exportedto .sdf (surface data file) format.

Individual sample .sdf files were analyzed using Nanovea® Ultra version6.2 by performing the following functions:

(1) Using the “Thresholding” function of the Nanovea® Ultra software,the raw image (also referred to as the field) is subjected tothresholding by setting the material ratio values at 0.5 to 99.5 percentsuch that thresholding truncates the measured heights to between the 0.5percentile height and the 99.5 percentile height;

(2) Using the “Fill In Non-Measured Points” function of the Nanovea®Ultra software the non-measured points are filled by a smooth shapecalculated from neighboring points;

(3) Using the “Filtering−Wavyness+Roughness” function of the Nanovea®Ultra software the field is spatially high pass filtered (roughness)using a Robust Gaussian Filter with a cutoff wavelength of 0.5 to 24.0mm and selecting “manage end effects”;

(4) Using the “Parameter Tables” study function of the Nanovea® Ultrasoftware ISO 25178 Values Sq (root mean square deviation, expressed inunits of mm) is calculated and reported;

(5) Using the “Abbott-Firestone Curve” study function of the Nanovea®Ultra software an Abbott-Firestone Curve is generated from which“interactive mode” is selected and a histogram of the measured heightsis generated, from the histogram an S90 value (95 percentile height (c2)minus the 5 percentile height (c1), expressed in units of mm) iscalculated.

Based upon the foregoing, two values, indicative of surface texture arereported—Sq and S90, which all have units of mm. The units have beenconverted to microns for use herein.

Compression Energy

Generally Compression Energy (E) refers to the energy required tocompress the sheet from its initial base sheet caliper down to its finalfinished product caliper. Compression Energy is calculated byintegrating the compression curve from the zero load height down to thefinished product caliper as:

E=∫_(c) _(fp) ⁰⁰PdC

where P is the pressure at any given caliper (C) and is defined as:

$P = {P_{0}\left( \frac{C_{0}}{C} \right)}^{K}$

where:

-   “P” is the pressure (MPa);-   “P₀” is a reference pressure equal to 0.002 MPa;-   “C” is the caliper of the stack under a pressure P of 1.0 psi,    measured during the second compression cycle;-   “C₀” is the initial caliper of the stack under the 0.002 MPa    reference pressure (having units of mm); and-   “K” is the finished product exponential compression modulus.

The “exponential compression modulus” (K) is found by least squaresfitting of the caliper (C) and pressure data from a compression curvefor the sample. The compression curve is measured by compressing a stackof twenty sheets between parallel plates on a suitable tensile frame(for example the MTS Systems Sintech 11S from MTS® Corporation). Theupper platen is to be 57 mm in diameter and the lower platen 89 mm indiameter. The stack of sheets should contain twenty sheets (102 mm by102 mm square) stacked with their machine direction and cross-machinedirections aligned. The sample stack should be placed between theplatens with a known separation of greater than the unloaded stackheight. The platens should then be brought together at a rate of 12.7mm/minute while the force is recorded with a suitable load cell (say 100N Self ID load cell from MTS® Corporation). The force data should beacquired and saved at 100 Hz. The compression should continue until theload exceeds 44.5 Newtons, at which point the platen should reversedirection and travel up at a rate of 12.7 mm/minute until the forcedecreases below 0.18 Newtons. The platen should then reverse directionagain and begin a second compression cycle at a rate of 12.7 mm/minuteuntil a load of 44.5 Newtons is exceeded. The load data should then beconverted to pressure data by dividing by the 2552 mm² contact area ofthe platens to give pressures in N/mm² or MPa. The pressure versus stackheight data for the second compression cycle between the pressures of0.07 kPa and 17.44 kPa is then least squares fit to the above expressionafter taking the logarithm of both sides to obtain:

In(P)=a−K In (C)

where “a” is a constant. The slope from the least squares fit is theexponential compression modulus (K). Five samples are to be tested percode and the average value of “K” reported.

By integrating the compression curve above, the Compression Energy (E)required to compress the sheet to any final caliper “C” is thus definedas follows:

$E = {{\int_{C}^{\infty}{PdC}} = \frac{P_{0}C_{0}^{K}}{\left( {K - 1} \right)C^{K - 1}}}$

where “K” is the exponential compression modulus (referred to herein asK) from the finished product test described above, “C” is the caliper ofthe stack under a pressure P of 1.0 psi, measured during the secondcompression cycle, and “C₀” is the initial caliper of the stack underthe 0.002 MPa reference pressure. When calculating the CompressionEnergy (E) for a given sheet, both C and Co are divided by the number ofsheets in the stack, here twenty sheets.

Roll Firmness

Roll Firmness was measured using the Kershaw Test as described in detailin U.S. Pat. No. 6,077,590, which is incorporated herein by reference ina manner consistent with the present disclosure. The apparatus isavailable from Kershaw Instrumentation, Inc. (Swedesboro, N.J.) and isknown as a Model RDT-2002 Roll Density Tester.

EXAMPLES

Base sheets were made using a through-air dried papermaking processcommonly referred to as “uncreped through-air dried” (“UCTAD”) andgenerally described in U.S. Pat. No. 5,607,551, the contents of whichare incorporated herein in a manner consistent with the presentinvention. Base sheets with a target bone dry basis weight of about 42grams per square meter (gsm) were produced. The base sheets were thenconverted and spirally wound into rolled tissue products.

In all cases the base sheets were produced from a furnish comprisingnorthern softwood kraft and eucalyptus kraft using a layered headbox fedby three stock chests such that the webs having three layers (two outerlayers and a middle layer) were formed. The two outer layers comprisedeucalyptus (each layer comprising 30 percent weight by total weight ofthe web) and the middle layer comprised softwood and eucalyptus. Theamount of softwood and eucalyptus kraft in the middle layer wasmaintained for all inventive samples—the middle layered comprised 29percent (by total weight of the web) softwood and 11 percent (by totalweight of the web) eucalyptus. Strength was controlled via the additionof a cationic strength agent, such as those marketed under the tradename FennoBond 3000 (Kemira Chemicals Inc., Atlanta, Ga.), cationicstarch, such as those marketed under the trade name Redibond 2038A(Ingredion, Westchester, Ill.) and/or by refining the furnish.

The tissue web was formed on a Voith Fabrics TissueForm V formingfabric, vacuum dewatered to approximately 25 percent consistency andthen subjected to rush transfer when transferred to the transfer fabric.The transfer fabric was the fabric described as “Fred” in U.S. Pat. No.7,611,607 (commercially available from Voith Fabrics, Appleton, Wis.).

The web was then transferred to a through-air drying fabric comprising aprinted silicone pattern disposed on the sheet contacting side. Thesilicone formed a wave-like pattern on the sheet contacting side of thefabric. The pattern properties are summarized in Table 3, below.

TABLE 3 Element Element Element CD Center-Center Height ElementWavelength Amplitude Spacing (mm) Angle (mm) (mm) (mm) 0.6 11.3 100 103.08Transfer to the through-drying fabric was done using vacuum levels ofabout 10 inches of mercury at the transfer. The web was then dried toapproximately 98 percent solids before winding. The base sheet wascalendered using a conventional polyurethane/steel calender systemcomprising a 40 P&J polyurethane roll on the air side of the sheet and astandard steel roll on the fabric side. The calender load was varied asset forth in Table 4, below. The calendered web was then converted intoa rolled product comprising a single-ply. The finished products weresubjected to physical analysis, which is summarized in Tables 4 and 5,below.

TABLE 4 Calender Load BW GMT Caliper Sheet Bulk Firmness Roll BulkSample (pli) (gsm) (g/3″) (microns) (cc/g) (mm) (cc/g) Roll Structure 140 41.7 839 630.8 15.0 5.9 11.88 1.27 2 150 42.2 877 594.4 14.0 7.511.59 0.92 3 40 41.3 1157 653.3 15.7 5.1 11.84 1.52 4 150 41.2 1269625.2 15.0 6.7 11.87 1.11

TABLE 5 GM Slope Stiffness C₀ E D Sample (kg) Index K (mm) (J/mm²) S90TS7 TS750 (mm/N) 1 5.32 6.34 5.187 9.753 0.01115 0.538 9.41 73.52 3.16 25.61 6.40 5.37 9.061 0.01094 0.482 8.53 74.89 3.27 3 6.21 5.36 5.33710.01 0.01178 0.529 10.54 79.98 2.96 4 6.07 4.78 5.23 9.281 0.010730.513 9.72 75.26 3.00

To further explore the relationship between the height of the lineelement used to mold the tissue web and the physical properties of theresulting tissue product, additional samples were prepared substantiallyas described above with the exception of the height of the through-airdrying fabric elements. The properties of the through-air drying fabricsused to manufacture the various samples are summarized in Table 6,below.

TABLE 6 CD Element Element Element Center-Center Height ElementWavelength Amplitude Spacing Sample (mm) Angle (mm) (mm) (mm) Inventive0.6 11.3 100 10 3.08 Control 1 0.9 21.8 100 20 4.6 Control 2 0.8 11.3100 10 4.1

The properties of the resulting base sheets are summarized in Table 7,below.

TABLE 7 Caliper Sheet Bulk GMT Sample (microns) (cc/g) (g/3″) Inventive1005 22.9 1536 Control 1 1295 34.6 1468 Control 2 1179 26.6 1545

The base sheet was calendered using a conventional polyurethane/steelcalender system comprising a 40 P&J polyurethane roll on the air side ofthe sheet and a standard steel roll on the fabric side. The calenderload was varied as set forth in Table 8. The calendered web was thenconverted into a rolled product comprising a single-ply. The finishedproducts were subjected to physical analysis, the results of which aresummarized in Tables 8 and 9, below.

TABLE 8 Calender Delta Delta Delta Load BW GMT Caliper Sheet BulkCaliper Sheet Bulk GMT Sample (Pli) (gsm) (g/3″) (microns) (cc/g) (%)(%) (%) Control 1-1 150 40.7 1265 571.0 14.0 −56% −59% −14% Control 2-1150 42.0 1235 608.1 14.5 −48% −46% −20% Inventive 1 150 41.2 1269 620.315.0 −38% −34% −17% Control 2-1 40 41.1 1303 623.8 15.2 −52% −56% −11%Control 2-2 40 41.8 1274 640.1 15.3 −46% −42% −18% Inventive 2 40 41.31157 648.2 15.7 −36% −31% −25%

TABLE 9 GM Slope Stiffness C₀ E D Sample (kg) Index K (mm) (J/mm²) S90TS7 TS750 (mm/N) Control 1-1 6.07 4.80 4.99 8.92 0.00960 0.591 11.3499.45 3.17 Control 2-1 6.44 5.22 4.83 9.19 0.00967 0.586 10.37 88.492.85 Inventive 1 6.07 4.78 5.23 9.28 0.01073 0.513 9.72 75.26 3.00Control 2-1 6.36 4.88 5.15 9.50 0.00984 0.641 11.98 107.39 3.32 Control2-2 6.44 5.05 4.83 9.37 0.00967 0.637 10.48 94.49 2.83 Inventive 2 6.215.36 5.34 10.01 0.01178 0.529 10.54 79.98 2.96

Accordingly, in a first embodiment the present invention provides anon-compressively dewatered single-ply tissue product comprising a firstand a second side and a topographical pattern comprising a plurality ofsubstantially machine direction oriented line elements disposed on afirst side thereof, the tissue product having a Compression Energy (E)greater than about 0.0100 J/mm², such as from about 0.0100 to about0.0130 J/mm², a GMT from about 500 to about 1,500 g/3″ and a sheet bulkgreater than about 15.0 cc/g.

In a second embodiment the present invention provides the tissue productof the first embodiment wound into a roll, the wound roll having aFirmness less than about 7.5 mm.

In a third embodiment the present invention provides the tissue productof the first or the second embodiment wherein the line elements areformed by manufacturing the tissue product using a through-air dryingfabric having corresponding line elements having a height less thanabout 0.7 mm.

In a fourth embodiment the present invention provides the tissue productof the first through the third embodiments wherein the line elements arecontinuous.

In a fifth embodiment the present invention provides the tissue productof the first through the fourth embodiments having a basis weight fromabout 25 to about 60 gsm and a caliper from about 600 to about 700microns.

In a sixth embodiment the present invention provides the tissue productof the first through the fifth embodiments having a TS7 less than about10.5 and a TS750 less than about 85.0.

In a seventh embodiment the present invention provides the tissueproduct of the first through the sixth embodiments having a StiffnessIndex less than about 7.5.

In an eighth embodiment the present invention provides a single-plynon-compressively dewatered tissue product having a caliper greater thanabout 600 μm, a Stiffness Index less than about 7.5 and a CompressionEnergy (E) greater than about 0.0100 J/mm².

In a ninth embodiment the present invention provides the tissue productof the eighth embodiment having a sheet bulk greater than about 15.0cc/g.

In a tenth embodiment the present invention provides the tissue productof the eighth or the ninth embodiments wherein the product comprises asingle-ply wound into a roll having a Roll Firmness less than about 7.5mm.

In an eleventh embodiment the present invention provides the tissueproduct of any one of the eighth through the tenth embodiments whereinthe web has been converted into a rolled tissue product having S90 lessthan about 0.55 mm.

In a twelfth embodiment the present invention provides the tissueproduct of any one of the eighth through the eleventh embodiments havinga GMT from about 700 to about 1,500 g/3″ and Basis Weight from about 25to about 60 gsm.

In a thirteenth embodiment the present invention provides the tissueproduct of any one of the eighth through the twelfth embodiments havinga K greater than about 5.0.

In a fourteenth embodiment the present invention provides the tissueproduct of any one of the eighth through the thirteenth embodimentshaving a Co greater than about 9.5 mm.

In a fifteenth embodiment the present invention provides the tissueproduct of any one of the eighth through the fourteenth embodimentshaving a TS7 less than about 10.5 and a TS750 less than about 85.0.

In a sixteenth embodiment the present invention provides a method ofmanufacturing a soft and resilient tissue product comprising the stepsof forming a fiber slurry; depositing the fiber slurry on a formingfabric; partially dewatering the slurry to form a wet tissue web;transferring the wet tissue web to a through-air drying fabriccomprising a support structure and a plurality of linear elementsextending in the z-direction therefrom, the elements having a heightfrom about 0.5 to about 0.7 mm; through-air drying the wet tissue web toform a dried tissue web; and calendering the dried tissue web andwinding the calendered web into a rolled tissue product having a RollFirmness less than about 7.5 mm and a sheet bulk greater than about 15.0cc/g.

In a seventeenth embodiment the present invention provides the method ofthe sixteenth embodiment wherein the step of calendering is carried outby passing the dried tissue web through a nip created by a steel rolland a polyurethane roll, the nip having a nip load from about 40 toabout 200 pli and more preferably from about 100 to about 160 pli.

In an eighteenth embodiment the present invention provides the method ofthe sixteenth or the seventeenth embodiments wherein the step ofcalendering comprises passing the web through a nip having a load of atleast about 40 pli, wherein the step of calendering reduces the sheetbulk less than about 50 percent.

In a nineteenth embodiment the present invention provides the method anyone of the sixteenth through eighteenth embodiments wherein the driedtissue web has a sheet bulk greater than about 15 cc/g and thecalendered web has a sheet bulk greater than about 12 cc/g.

We claim:
 1. A method of manufacturing a soft and resilient tissueproduct comprising the steps of: a. forming a fiber slurry; b.depositing the fiber slurry on a forming fabric; c. partially dewateringthe slurry to form a wet tissue web; d. transferring the wet tissue webto a through-air drying fabric comprising a support structure and aplurality of linear elements extending in the z-direction therefrom, theelements having a height from about 0.4 to about 0.7 mm; e. through-airdrying the wet tissue web to form a dried tissue web; and f. calenderingthe dried tissue web and winding the calendered web into a rolled tissueproduct having a Roll Firmness less than about 7.5 mm and a sheet bulkgreater than about 15.0 cc/g.
 2. The method of claim 1 wherein the stepof calendering is carried out by passing the dried tissue web through anip created by a steel roll and a polyurethane roll, the nip having anip load from about 20 to about 200 pli.
 3. The method of claim 1wherein the rolled tissue product has a caliper greater than about 600microns.
 4. The method of claim 1 wherein the rolled tissue product hasa S90 from about 0.45 to about 0.55 mm.
 5. The method of claim 1 whereinthe rolled tissue product has a Caliper Under Load (C₀) from about 9.5to about 10.5.
 6. The method of claim 1 wherein the rolled tissueproduct has a Compression Energy (E) from about 0.010 to about 0.0130J/mm².